drivers/staging/rtl8187se/ieee80211/ieee80211_crypt_ccmp.c

   1 /*
   2  * Host AP crypt: host-based CCMP encryption implementation for Host AP driver
   3  *
   4  * Copyright (c) 2003-2004, Jouni Malinen <jkmaline@cc.hut.fi>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation. See README and COPYING for
   9  * more details.
  10  */
  11
  12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  13
  14 //#include <linux/config.h>
  15 #include <linux/module.h>
  16 #include <linux/init.h>
  17 #include <linux/slab.h>
  18 #include <linux/random.h>
  19 #include <linux/skbuff.h>
  20 #include <linux/netdevice.h>
  21 #include <linux/if_ether.h>
  22 #include <linux/if_arp.h>
  23 #include <linux/string.h>
  24 #include <linux/wireless.h>
  25
  26 #include "ieee80211.h"
  27
  28 #include <linux/crypto.h>
  29 #include <linux/scatterlist.h>
  30
  31 MODULE_AUTHOR("Jouni Malinen");
  32 MODULE_DESCRIPTION("Host AP crypt: CCMP");
  33 MODULE_LICENSE("GPL");
  34
  35
  36 #define AES_BLOCK_LEN 16
  37 #define CCMP_HDR_LEN 8
  38 #define CCMP_MIC_LEN 8
  39 #define CCMP_TK_LEN 16
  40 #define CCMP_PN_LEN 6
  41
  42 struct ieee80211_ccmp_data {
  43         u8 key[CCMP_TK_LEN];
  44         int key_set;
  45
  46         u8 tx_pn[CCMP_PN_LEN];
  47         u8 rx_pn[CCMP_PN_LEN];
  48
  49         u32 dot11RSNAStatsCCMPFormatErrors;
  50         u32 dot11RSNAStatsCCMPReplays;
  51         u32 dot11RSNAStatsCCMPDecryptErrors;
  52
  53         int key_idx;
  54
  55         struct crypto_tfm *tfm;
  56
  57         /* scratch buffers for virt_to_page() (crypto API) */
  58         u8 tx_b0[AES_BLOCK_LEN], tx_b[AES_BLOCK_LEN],
  59                 tx_e[AES_BLOCK_LEN], tx_s0[AES_BLOCK_LEN];
  60         u8 rx_b0[AES_BLOCK_LEN], rx_b[AES_BLOCK_LEN], rx_a[AES_BLOCK_LEN];
  61 };
  62
  63 void ieee80211_ccmp_aes_encrypt(struct crypto_tfm *tfm,
  64                              const u8 pt[16], u8 ct[16])
  65 {
  66         crypto_cipher_encrypt_one((void *)tfm, ct, pt);
  67 }
  68
  69 static void *ieee80211_ccmp_init(int key_idx)
  70 {
  71         struct ieee80211_ccmp_data *priv;
  72
  73         priv = kzalloc(sizeof(*priv), GFP_ATOMIC);
  74         if (priv == NULL)
  75                 goto fail;
  76         priv->key_idx = key_idx;
  77
  78         priv->tfm = (void *)crypto_alloc_cipher("aes", 0, CRYPTO_ALG_ASYNC);
  79         if (IS_ERR(priv->tfm)) {
  80                 pr_debug("could not allocate crypto API aes\n");
  81                 priv->tfm = NULL;
  82                 goto fail;
  83         }
  84
  85         return priv;
  86
  87 fail:
  88         if (priv) {
  89                 if (priv->tfm)
  90                         crypto_free_cipher((void *)priv->tfm);
  91                 kfree(priv);
  92         }
  93
  94         return NULL;
  95 }
  96
  97
  98 static void ieee80211_ccmp_deinit(void *priv)
  99 {
 100         struct ieee80211_ccmp_data *_priv = priv;
 101
 102         if (_priv && _priv->tfm)
 103                 crypto_free_cipher((void *)_priv->tfm);
 104         kfree(priv);
 105 }
 106
 107
 108 static inline void xor_block(u8 *b, u8 *a, size_t len)
 109 {
 110         int i;
 111         for (i = 0; i < len; i++)
 112                 b[i] ^= a[i];
 113 }
 114
 115 static void ccmp_init_blocks(struct crypto_tfm *tfm,
 116                              struct ieee80211_hdr_4addr *hdr,
 117                              u8 *pn, size_t dlen, u8 *b0, u8 *auth,
 118                              u8 *s0)
 119 {
 120         u8 *pos, qc = 0;
 121         size_t aad_len;
 122         u16 fc;
 123         int a4_included, qc_included;
 124         u8 aad[2 * AES_BLOCK_LEN];
 125
 126         fc = le16_to_cpu(hdr->frame_ctl);
 127         a4_included = ((fc & (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS)) ==
 128                        (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS));
 129         /*
 130         qc_included = ((WLAN_FC_GET_TYPE(fc) == IEEE80211_FTYPE_DATA) &&
 131                        (WLAN_FC_GET_STYPE(fc) & 0x08));
 132         */
 133         // fixed by David :2006.9.6
 134         qc_included = ((WLAN_FC_GET_TYPE(fc) == IEEE80211_FTYPE_DATA) &&
 135                        (WLAN_FC_GET_STYPE(fc) & 0x80));
 136         aad_len = 22;
 137         if (a4_included)
 138                 aad_len += 6;
 139         if (qc_included) {
 140                 pos = (u8 *) &hdr->addr4;
 141                 if (a4_included)
 142                         pos += 6;
 143                 qc = *pos & 0x0f;
 144                 aad_len += 2;
 145         }
 146         /* CCM Initial Block:
 147          * Flag (Include authentication header, M=3 (8-octet MIC),
 148          *       L=1 (2-octet Dlen))
 149          * Nonce: 0x00 | A2 | PN
 150          * Dlen */
 151         b0[0] = 0x59;
 152         b0[1] = qc;
 153         memcpy(b0 + 2, hdr->addr2, ETH_ALEN);
 154         memcpy(b0 + 8, pn, CCMP_PN_LEN);
 155         b0[14] = (dlen >> 8) & 0xff;
 156         b0[15] = dlen & 0xff;
 157
 158         /* AAD:
 159          * FC with bits 4..6 and 11..13 masked to zero; 14 is always one
 160          * A1 | A2 | A3
 161          * SC with bits 4..15 (seq#) masked to zero
 162          * A4 (if present)
 163          * QC (if present)
 164          */
 165         pos = (u8 *) hdr;
 166         aad[0] = 0; /* aad_len >> 8 */
 167         aad[1] = aad_len & 0xff;
 168         aad[2] = pos[0] & 0x8f;
 169         aad[3] = pos[1] & 0xc7;
 170         memcpy(aad + 4, hdr->addr1, 3 * ETH_ALEN);
 171         pos = (u8 *) &hdr->seq_ctl;
 172         aad[22] = pos[0] & 0x0f;
 173         aad[23] = 0; /* all bits masked */
 174         memset(aad + 24, 0, 8);
 175         if (a4_included)
 176                 memcpy(aad + 24, hdr->addr4, ETH_ALEN);
 177         if (qc_included) {
 178                 aad[a4_included ? 30 : 24] = qc;
 179                 /* rest of QC masked */
 180         }
 181
 182         /* Start with the first block and AAD */
 183         ieee80211_ccmp_aes_encrypt(tfm, b0, auth);
 184         xor_block(auth, aad, AES_BLOCK_LEN);
 185         ieee80211_ccmp_aes_encrypt(tfm, auth, auth);
 186         xor_block(auth, &aad[AES_BLOCK_LEN], AES_BLOCK_LEN);
 187         ieee80211_ccmp_aes_encrypt(tfm, auth, auth);
 188         b0[0] &= 0x07;
 189         b0[14] = b0[15] = 0;
 190         ieee80211_ccmp_aes_encrypt(tfm, b0, s0);
 191 }
 192
 193 static int ieee80211_ccmp_encrypt(struct sk_buff *skb, int hdr_len, void *priv)
 194 {
 195         struct ieee80211_ccmp_data *key = priv;
 196         int data_len, i;
 197         u8 *pos;
 198         struct ieee80211_hdr_4addr *hdr;
 199         int blocks, last, len;
 200         u8 *mic;
 201         u8 *b0 = key->tx_b0;
 202         u8 *b = key->tx_b;
 203         u8 *e = key->tx_e;
 204         u8 *s0 = key->tx_s0;
 205
 206         if (skb_headroom(skb) < CCMP_HDR_LEN ||
 207             skb_tailroom(skb) < CCMP_MIC_LEN ||
 208             skb->len < hdr_len)
 209                 return -1;
 210
 211         data_len = skb->len - hdr_len;
 212         pos = skb_push(skb, CCMP_HDR_LEN);
 213         memmove(pos, pos + CCMP_HDR_LEN, hdr_len);
 214         pos += hdr_len;
 215 //      mic = skb_put(skb, CCMP_MIC_LEN);
 216
 217         i = CCMP_PN_LEN - 1;
 218         while (i >= 0) {
 219                 key->tx_pn[i]++;
 220                 if (key->tx_pn[i] != 0)
 221                         break;
 222                 i--;
 223         }
 224
 225         *pos++ = key->tx_pn[5];
 226         *pos++ = key->tx_pn[4];
 227         *pos++ = 0;
 228         *pos++ = (key->key_idx << 6) | (1 << 5) /* Ext IV included */;
 229         *pos++ = key->tx_pn[3];
 230         *pos++ = key->tx_pn[2];
 231         *pos++ = key->tx_pn[1];
 232         *pos++ = key->tx_pn[0];
 233
 234         hdr = (struct ieee80211_hdr_4addr *)skb->data;
 235         //mic is moved to here by john
 236         mic = skb_put(skb, CCMP_MIC_LEN);
 237
 238         ccmp_init_blocks(key->tfm, hdr, key->tx_pn, data_len, b0, b, s0);
 239
 240         blocks = (data_len + AES_BLOCK_LEN - 1) / AES_BLOCK_LEN;
 241         last = data_len % AES_BLOCK_LEN;
 242
 243         for (i = 1; i <= blocks; i++) {
 244                 len = (i == blocks && last) ? last : AES_BLOCK_LEN;
 245                 /* Authentication */
 246                 xor_block(b, pos, len);
 247                 ieee80211_ccmp_aes_encrypt(key->tfm, b, b);
 248                 /* Encryption, with counter */
 249                 b0[14] = (i >> 8) & 0xff;
 250                 b0[15] = i & 0xff;
 251                 ieee80211_ccmp_aes_encrypt(key->tfm, b0, e);
 252                 xor_block(pos, e, len);
 253                 pos += len;
 254         }
 255
 256         for (i = 0; i < CCMP_MIC_LEN; i++)
 257                 mic[i] = b[i] ^ s0[i];
 258
 259         return 0;
 260 }
 261
 262
 263 static int ieee80211_ccmp_decrypt(struct sk_buff *skb, int hdr_len, void *priv)
 264 {
 265         struct ieee80211_ccmp_data *key = priv;
 266         u8 keyidx, *pos;
 267         struct ieee80211_hdr_4addr *hdr;
 268         u8 pn[6];
 269         size_t data_len = skb->len - hdr_len - CCMP_HDR_LEN - CCMP_MIC_LEN;
 270         u8 *mic = skb->data + skb->len - CCMP_MIC_LEN;
 271         u8 *b0 = key->rx_b0;
 272         u8 *b = key->rx_b;
 273         u8 *a = key->rx_a;
 274         int i, blocks, last, len;
 275
 276         if (skb->len < hdr_len + CCMP_HDR_LEN + CCMP_MIC_LEN) {
 277                 key->dot11RSNAStatsCCMPFormatErrors++;
 278                 return -1;
 279         }
 280
 281         hdr = (struct ieee80211_hdr_4addr *)skb->data;
 282         pos = skb->data + hdr_len;
 283         keyidx = pos[3];
 284         if (!(keyidx & (1 << 5))) {
 285                 if (net_ratelimit()) {
 286                         pr_debug("received packet without ExtIV flag from %pM\n",
 287                                  hdr->addr2);
 288                 }
 289                 key->dot11RSNAStatsCCMPFormatErrors++;
 290                 return -2;
 291         }
 292         keyidx >>= 6;
 293         if (key->key_idx != keyidx) {
 294                 pr_debug("RX tkey->key_idx=%d frame keyidx=%d priv=%p\n",
 295                          key->key_idx, keyidx, priv);
 296                 return -6;
 297         }
 298         if (!key->key_set) {
 299                 if (net_ratelimit()) {
 300                         pr_debug("received packet from %pM with keyid=%d that does not have a configured key\n",
 301                                  hdr->addr2, keyidx);
 302                 }
 303                 return -3;
 304         }
 305
 306         pn[0] = pos[7];
 307         pn[1] = pos[6];
 308         pn[2] = pos[5];
 309         pn[3] = pos[4];
 310         pn[4] = pos[1];
 311         pn[5] = pos[0];
 312         pos += 8;
 313
 314         if (memcmp(pn, key->rx_pn, CCMP_PN_LEN) <= 0) {
 315                 if (net_ratelimit()) {
 316                         pr_debug("replay detected: STA=%pM previous PN %pm received PN %pm\n",
 317                                  hdr->addr2, key->rx_pn, pn);
 318                 }
 319                 key->dot11RSNAStatsCCMPReplays++;
 320                 return -4;
 321         }
 322
 323         ccmp_init_blocks(key->tfm, hdr, pn, data_len, b0, a, b);
 324         xor_block(mic, b, CCMP_MIC_LEN);
 325
 326         blocks = (data_len + AES_BLOCK_LEN - 1) / AES_BLOCK_LEN;
 327         last = data_len % AES_BLOCK_LEN;
 328
 329         for (i = 1; i <= blocks; i++) {
 330                 len = (i == blocks && last) ? last : AES_BLOCK_LEN;
 331                 /* Decrypt, with counter */
 332                 b0[14] = (i >> 8) & 0xff;
 333                 b0[15] = i & 0xff;
 334                 ieee80211_ccmp_aes_encrypt(key->tfm, b0, b);
 335                 xor_block(pos, b, len);
 336                 /* Authentication */
 337                 xor_block(a, pos, len);
 338                 ieee80211_ccmp_aes_encrypt(key->tfm, a, a);
 339                 pos += len;
 340         }
 341
 342         if (memcmp(mic, a, CCMP_MIC_LEN) != 0) {
 343                 if (net_ratelimit())
 344                         pr_debug("decrypt failed: STA=%pM\n", hdr->addr2);
 345
 346                 key->dot11RSNAStatsCCMPDecryptErrors++;
 347                 return -5;
 348         }
 349
 350         memcpy(key->rx_pn, pn, CCMP_PN_LEN);
 351
 352         /* Remove hdr and MIC */
 353         memmove(skb->data + CCMP_HDR_LEN, skb->data, hdr_len);
 354         skb_pull(skb, CCMP_HDR_LEN);
 355         skb_trim(skb, skb->len - CCMP_MIC_LEN);
 356
 357         return keyidx;
 358 }
 359
 360
 361 static int ieee80211_ccmp_set_key(void *key, int len, u8 *seq, void *priv)
 362 {
 363         struct ieee80211_ccmp_data *data = priv;
 364         int keyidx;
 365         struct crypto_tfm *tfm = data->tfm;
 366
 367         keyidx = data->key_idx;
 368         memset(data, 0, sizeof(*data));
 369         data->key_idx = keyidx;
 370         data->tfm = tfm;
 371         if (len == CCMP_TK_LEN) {
 372                 memcpy(data->key, key, CCMP_TK_LEN);
 373                 data->key_set = 1;
 374                 if (seq) {
 375                         data->rx_pn[0] = seq[5];
 376                         data->rx_pn[1] = seq[4];
 377                         data->rx_pn[2] = seq[3];
 378                         data->rx_pn[3] = seq[2];
 379                         data->rx_pn[4] = seq[1];
 380                         data->rx_pn[5] = seq[0];
 381                 }
 382                 crypto_cipher_setkey((void *)data->tfm, data->key, CCMP_TK_LEN);
 383         } else if (len == 0)
 384                 data->key_set = 0;
 385         else
 386                 return -1;
 387
 388         return 0;
 389 }
 390
 391
 392 static int ieee80211_ccmp_get_key(void *key, int len, u8 *seq, void *priv)
 393 {
 394         struct ieee80211_ccmp_data *data = priv;
 395
 396         if (len < CCMP_TK_LEN)
 397                 return -1;
 398
 399         if (!data->key_set)
 400                 return 0;
 401         memcpy(key, data->key, CCMP_TK_LEN);
 402
 403         if (seq) {
 404                 seq[0] = data->tx_pn[5];
 405                 seq[1] = data->tx_pn[4];
 406                 seq[2] = data->tx_pn[3];
 407                 seq[3] = data->tx_pn[2];
 408                 seq[4] = data->tx_pn[1];
 409                 seq[5] = data->tx_pn[0];
 410         }
 411
 412         return CCMP_TK_LEN;
 413 }
 414
 415
 416 static char *ieee80211_ccmp_print_stats(char *p, void *priv)
 417 {
 418         struct ieee80211_ccmp_data *ccmp = priv;
 419         p += sprintf(p, "key[%d] alg=CCMP key_set=%d "
 420                      "tx_pn=%pm rx_pn=%pm "
 421                      "format_errors=%d replays=%d decrypt_errors=%d\n",
 422                      ccmp->key_idx, ccmp->key_set,
 423                      ccmp->tx_pn, ccmp->rx_pn,
 424                      ccmp->dot11RSNAStatsCCMPFormatErrors,
 425                      ccmp->dot11RSNAStatsCCMPReplays,
 426                      ccmp->dot11RSNAStatsCCMPDecryptErrors);
 427
 428         return p;
 429 }
 430
 431 void ieee80211_ccmp_null(void)
 432 {
 433 //    printk("============>%s()\n", __func__);
 434         return;
 435 }
 436 static struct ieee80211_crypto_ops ieee80211_crypt_ccmp = {
 437         .name                   = "CCMP",
 438         .init                   = ieee80211_ccmp_init,
 439         .deinit                 = ieee80211_ccmp_deinit,
 440         .encrypt_mpdu           = ieee80211_ccmp_encrypt,
 441         .decrypt_mpdu           = ieee80211_ccmp_decrypt,
 442         .encrypt_msdu           = NULL,
 443         .decrypt_msdu           = NULL,
 444         .set_key                = ieee80211_ccmp_set_key,
 445         .get_key                = ieee80211_ccmp_get_key,
 446         .print_stats            = ieee80211_ccmp_print_stats,
 447         .extra_prefix_len       = CCMP_HDR_LEN,
 448         .extra_postfix_len      = CCMP_MIC_LEN,
 449         .owner                  = THIS_MODULE,
 450 };
 451
 452
 453 int ieee80211_crypto_ccmp_init(void)
 454 {
 455         return ieee80211_register_crypto_ops(&ieee80211_crypt_ccmp);
 456 }
 457
 458
 459 void ieee80211_crypto_ccmp_exit(void)
 460 {
 461         ieee80211_unregister_crypto_ops(&ieee80211_crypt_ccmp);
 462 }